Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

Methods and devices are disclosed for supporting and holding open a
tubular structure in the body of an animal or human. In one form, the
device is a manually adjustable variable outside diameter stent that can
be repositioned or removed. The stent includes an elastic tubular body
and an adjustment mechanism for the moving two ends of the body toward or
away from each other. The elastic tubular body comprises a braiding of
two groups of spaced apart helically wound elastic strands. The
adjustment mechanism includes a bracket, a tension adjustor, and a
tensioning wire attached to the bracket and the tension adjuster. The
bracket and the tension adjuster are attached to one or more of the
elastic strands of the two groups. Using the adjustment mechanism, the
distance between the bracket and the tension adjustor can be decreased
causing the outside diameter of the body to increase, or vice versa.

Claims:

1. A stent comprising: an elastic tubular body having a first end and an
opposite second end and an outside diameter, the body comprising a
braiding of a first group of spaced apart helically wound first elastic
strands and a second group of spaced apart helically wound second elastic
strands such that the outside diameter of the body increases when the
first end of the body is moved towards the second end of the body, and
such that the outside diameter of the body decreases when the first end
of the body moves away from the second end of the body; and an adjustment
mechanism for the moving the first end of the body toward or away from
the second end of the body, the adjustment mechanism including a bracket,
a tension adjustor, and a tensioning wire attached to the bracket and the
tension adjustor such that the bracket and the tension adjustor are in
spaced apart relationship, the bracket being attached to at least one of
the first elastic strands and the second elastic strands, the tension
adjustor being attached to at least one of the first elastic strands and
the second elastic strands, wherein a distance between the bracket and
the tension adjustor can be varied to move the first end of the body
towards the second end of the body or to move the first end of the body
away from the second end of the body.

2. The stent of claim 1 wherein: the tension adjustor comprises a housing
having a hole with internal threads that mate with an external threaded
section of the tensioning wire, and the distance between the bracket and
the tension adjustor can be varied by rotating the tensioning wire with
respect to the hole.

3. The stent of claim 2 wherein: a distal end of the tensioning wire is
rotatably attached to the bracket.

4. The stent of claim 2 wherein: a proximal end of the tensioning wire
terminates in an enlarged head that is located within an interior space
of the housing.

5. The stent of claim 3 wherein: the enlarged head of the tensioning wire
is structured to be engageable with a tool.

6. The stent of claim 3 wherein: the housing includes an opening, and the
stent further includes a movable cover attached to the housing, the cover
including a first position in which the opening is closed off and a
second position providing access to the end of the tensioning wire.

7. The stent of claim 1 further comprising: a guide ring surrounding the
tensioning wire, the guide ring being attached to at least one of the
first elastic strands and the second elastic strands, the guide ring
being located between the bracket and the tension adjustor.

8. The stent of claim 7 wherein: the tensioning wire and the guide ring
contact at a bearing surface.

9. The stent of claim 1 wherein: the bracket is attached at an
intersection of at least one of the first elastic strands and at least
one of the second elastic strands, and the tension adjustor is attached
at an intersection of at least one of the first elastic strands and at
least one of the second elastic strands.

10. The stent of claim 1 wherein: the first end of the body is
circumferential and the bracket is attached to at least one of the first
elastic strands and the second elastic strands comprising the first end
of the body.

11. The stent of claim 1 wherein: the second end of the body is
circumferential and the tension adjustor is attached to at least one of
the first elastic strands and the second elastic strands comprising the
second end of the body.

12. The stent of claim 1 further comprising: a second adjustment
mechanism for the moving a first section of the body toward or away from
the second section of the body, the second adjustment mechanism including
a second bracket, a second tension adjustor, and a second tensioning wire
attached to the second bracket and the second tension adjustor such that
the second bracket and the second tension adjustor are in spaced apart
relationship, the second bracket being attached to at least one of the
first elastic strands and the second elastic strands, the second tension
adjustor being attached to at least one of the first elastic strands and
the second elastic strands, wherein a distance between the second bracket
and the second tension adjustor can be varied to move the first section
of the body towards the second section of the body or to move the first
section of the body away from the second section of the body.

13. The stent of claim 1 wherein: the stent is a self-expanding stent.

14. The stent of claim 1 wherein: the stent is a balloon expandable
stent.

15. A device for supporting and holding open a tubular structure in an
animal or human, the device comprising: the stent of claim 1; and a tool
for varying the distance between the bracket and the tension adjustor.

16. The device of claim 15 wherein: the tension adjustor comprises a
housing having a hole with internal threads that mate with an external
threaded section of the tensioning wire, and the distance between the
bracket and the tension adjustor can be varied by engaging the tensioning
wire with the tool and rotating the tensioning wire with respect to the
hole.

17. The device of claim 16 wherein: a proximal end of the tensioning wire
terminates in an enlarged head that is located within an interior space
of the housing, and the enlarged head of the tensioning wire is
structured to be engageable with a distal end of the tool.

18. The device of claim 15 wherein: the tool comprises a cable suitable
for insertion into the tubular structure in the animal or human, the
cable terminating in a tip for engaging the enlarged head of the
tensioning wire.

19. The device of claim 18 wherein: the tool further comprises a sheath
including a passageway having a distal opening, the passageway being
dimensioned for insertion of the cable such that the tip of the cable can
protrude beyond the distal opening of the passageway.

20. A method for positioning a stent in a tubular structure in an animal
or human, the method comprising: (a) providing a stent comprising (i) an
elastic tubular body having a first end and an opposite second end and an
outside diameter, the body comprising a braiding of a first group of
spaced apart helically wound first elastic strands and a second group of
spaced apart helically wound second elastic strands such that the outside
diameter of the body increases when the first end of the body is moved
towards the second end of the body, and such that the outside diameter of
the body decreases when the first end of the body moves away from the
second end of the body; and (ii) an adjustment mechanism for the moving
the first end of the body toward or away from the second end of the body,
the adjustment mechanism including a bracket, a tension adjustor, and a
tensioning wire attached to the bracket and the tension adjustor such
that the bracket and the tension adjustor are in spaced apart
relationship, the bracket being attached to at least one of the first
elastic strands and the second elastic strands, the tension adjustor
being attached to at least one of the first elastic strands and the
second elastic strands; (b) positioning the stent in the tubular
structure in the animal or human; and (c) causing the outside diameter of
the body to engage an inner surface of the tubular structure in the
animal or human.

21. The method of claim 20 wherein: step (c) comprises using the tension
adjustor to decrease a distance between the bracket and the tension
adjustor to move the first end of the body towards the second end of the
body such that the outside diameter of the body increases and engages the
inner surface of the tubular structure in the animal or human.

22. The method of claim 20 further comprising: (d) using the tension
adjustor to increase a distance between the bracket and the tension
adjustor to move the first end of the body away from the second end of
the body such that the outside diameter of the body decreases and
disengages from the inner surface of the tubular structure in the animal
or human.

23. The method of claim 22 further comprising: (e) repositioning the
stent in a second location in the tubular structure in the animal or
human; and (f) causing the outside diameter of the body to engage the
inner surface of the tubular structure in the animal or human at the
second location.

24. The method of claim 22 further comprising: (e) removing the stent
from the tubular structure in the animal or human.

25. The method of claim 20 wherein: step (c) comprises restraining the
stent in a sheath and retracting the sheath such that the outside
diameter of the body increases and engages the inner surface of the
tubular structure in the animal or human.

26. The method of claim 20 wherein: step (c) comprises mounting the stent
on a balloon and inflating the balloon such that the outside diameter of
the body increases and engages the inner surface of the tubular structure
in the animal or human.

[0004] The invention relates to methods and devices for supporting and
holding open a tubular structure in the body of an animal or human. In
particular, the invention relates to a stent that can be repositioned or
removed once deployed.

[0005] 2. Description of the Related Art

[0006] A stent is a device that can be placed within a body lumen for
supporting and holding open a tubular structure in the body of an animal
or human. In one common application, a stent is used for holding open a
blood vessel. However, a stent can be used inside the lumen of any
physiological conduit including arteries, veins, vessels, the biliary
tree, the urinary tract, the alimentary tract, the tracheal bronchial
tree, the genitourinary system, and the cerebral aqueduct.

[0007] Stents are generally tubular in structure and are radially
expandable between an unexpanded insertion diameter and an expanded
implantation diameter which is greater than the unexpanded insertion
diameter. A stent is passed through the tubular structure in the body
when collapsed, and then the stent will expand or can be expanded to its
expanded implantation diameter after the implantation location has been
reached.

[0008] Stents are generally categorized as being self-expanding, i.e., the
stent expands by itself, or balloon expandable, i.e., the stent is
expanded by a balloon inserted inside the stent. In one method for
deploying a self-expanding stent, the stent is restrained within a
sheath. After positioning of the self-expanding stent and sheath at the
desired location in the lumen, the physician retracts the sheath to
expose the stent and allow the stent to self-expand. In one method for
deploying a balloon expandable stent, a delivery catheter assembly with
an expandable balloon is used to deliver the stent. The stent is mounted
on the balloon and the catheter assembly is pushed into the implantation
site. Then, the balloon is inflated, radially applying a force inside the
stent, and the stent is expanded to its expanded implantation diameter.

[0009] One problem with known stents is that they can be difficult to
reposition or remove once deployed. Once a conventional stent is
positioned in a particular tubular structure in the body and expanded in
place, the stent cannot be reduced in diameter for repositioning or
removal.

[0010] Thus, there exists a need for an improved stent that has an
adjustable outside diameter such that the stent can be repositioned in,
or removed from, a tubular structure in the body.

SUMMARY OF THE INVENTION

[0011] The present invention addresses the foregoing needs by providing a
stent that has an adjustable outside diameter such that the stent can be
repositioned in, or removed from, a tubular structure in the body. The
stent includes an elastic tubular body and an adjustment mechanism for
the moving the first end of the body toward or away from the second end
of the body such that the outside diameter of the body increases when the
first end of the body is moved towards the second end of the body, and
such that the outside diameter of the body decreases when the first end
of the body moves away from the second end of the body.

[0012] The elastic tubular body comprises a braiding of a first group of
spaced apart helically wound first elastic strands and a second group of
spaced apart helically wound second elastic strands. The adjustment
mechanism includes a bracket, a tension adjustor, and a tensioning wire
attached to the bracket and the tension adjustor such that the bracket
and the tension adjustor are in spaced apart relationship. The bracket
and the tension adjustor are attached to one or more of the first elastic
strands and the second elastic strands. Using the adjustment mechanism,
the distance between the bracket and the tension adjustor can be
decreased causing the outside diameter of the body to increase, or the
distance between the bracket and the tension adjustor can be increased
causing the outside diameter of the body to decrease.

[0013] The tension adjustor can include a housing having a hole with
internal threads that mate with an external threaded section of the
tensioning wire, and the distance between the bracket and the tension
adjustor can be varied by rotating the tensioning wire with respect to
the hole. A distal end of the tensioning wire can be rotatably attached
to the bracket. A proximal end of the tensioning wire can terminate in an
enlarged head that is located within an interior space of the housing.
The enlarged head of the tensioning wire can be structured to be
engageable with a tool. The housing can include an opening, and the stent
can further include a movable cover attached to the housing. The cover
can include a first position in which the opening is closed off and a
second position providing access to the end of the tensioning wire.

[0014] The stent can include a guide ring surrounding the tensioning wire.
The guide ring can be attached to at least one of the first elastic
strands and the second elastic strands, and the guide ring can be located
between the bracket and the tension adjustor. The tensioning wire and the
guide ring can contact at a bearing surface.

[0015] The bracket can be attached at an intersection of at least one of
the first elastic strands and at least one of the second elastic strands,
and the tension adjustor can be attached at an intersection of at least
one of the first elastic strands and at least one of the second elastic
strands. The first end of the body can be circumferential and the bracket
can be attached to at least one of the first elastic strands and the
second elastic strands comprising the first end of the body. The second
end of the body can be circumferential and the tension adjustor can be
attached to at least one of the first elastic strands and the second
elastic strands comprising the second end of the body.

[0016] The stent can further include a second adjustment mechanism for the
moving a first section of the body toward or away from the second section
of the body. The second adjustment mechanism can include a second
bracket, a second tension adjustor, and a second tensioning wire attached
to the second bracket and the second tension adjustor such that the
second bracket and the second tension adjustor are in spaced apart
relationship. The second bracket can be attached to at least one of the
first elastic strands and the second elastic strands, and the second
tension adjustor can be attached to at least one of the first elastic
strands and the second elastic strands. A distance between the second
bracket and the second tension adjustor can be varied to move the first
section of the body towards the second section of the body or to move the
first section of the body away from the second section of the body.

[0017] In one form, the stent is a self-expanding stent. In another form,
the stent is a balloon expandable stent.

[0018] In another aspect, the invention includes a tool for varying the
distance between the bracket and the tension adjustor. After a stent is
deployed to engage the inner surface of the tubular structure in the
animal or human, the tool can be used to operate the tension adjustor to
increase the distance between the bracket and the tension adjustor to
move the first end of the body away from the second end of the body such
that the outside diameter of the body decreases and disengages from the
inner surface of the tubular structure in the animal or human. The stent
can then be repositioned in a second location in the tubular structure,
or removed from the tubular structure.

[0019] The tension adjustor can include a housing having a hole with
internal threads that mate with an external threaded section of the
tensioning wire, and the distance between the bracket and the tension
adjustor can be varied by engaging the tensioning wire with the tool and
rotating the tensioning wire with respect to the hole. A proximal end of
the tensioning wire can terminate in an enlarged head that is located
within an interior space of the housing, and the enlarged head of the
tensioning wire can be structured to be engageable with a distal end of
the tool.

[0020] The tool can include a cable suitable for insertion into the
tubular structure in the animal or human, wherein the cable terminates in
a tip for engaging the enlarged head of the tensioning wire. The tool can
further include a sheath including a passageway having a distal opening,
wherein the passageway is dimensioned for insertion of the cable such
that the tip of the cable can protrude beyond the distal opening of the
passageway.

[0021] In yet another aspect, the invention provides a method for
positioning a stent in a tubular structure in an animal or human. The
stent can include an elastic tubular body having a first end and an
opposite second end and an outside diameter. The body can include a
braiding of a first group of spaced apart helically wound first elastic
strands and a second group of spaced apart helically wound second elastic
strands such that the outside diameter of the body increases when the
first end of the body is moved towards the second end of the body, and
such that the outside diameter of the body decreases when the first end
of the body moves away from the second end of the body. The stent can
further include an adjustment mechanism for the moving the first end of
the body toward or away from the second end of the body. The adjustment
mechanism can include a bracket, a tension adjustor, and a tensioning
wire attached to the bracket and the tension adjustor such that the
bracket and the tension adjustor are in spaced apart relationship. The
bracket can be attached to at least one of the first elastic strands and
the second elastic strands, and the tension adjustor can be attached to
at least one of the first elastic strands and the second elastic strands.
The stent is positioned in the tubular structure in the animal or human,
and the outside diameter of the body is caused to engage an inner surface
of the tubular structure in the animal or human.

[0022] The tension adjustor can be used to decrease a distance between the
bracket and the tension adjustor to move the first end of the body
towards the second end of the body such that the outside diameter of the
body increases and engages the inner surface of the tubular structure in
the animal or human. The tension adjustor can be used to increase a
distance between the bracket and the tension adjustor to move the first
end of the body away from the second end of the body such that the
outside diameter of the body decreases and disengages from the inner
surface of the tubular structure in the animal or human. The stent can be
repositioned in a second location in the tubular structure in the animal
or human, and the outside diameter of the body can be caused to engage
the inner surface of the tubular structure in the animal or human at the
second location. Alternatively, the stent can be removed from the tubular
structure in the animal or human after disengaging the stent from the
inner surface of the tubular structure in the animal or human.

[0023] The stent can be caused to engage an inner surface of the tubular
structure in the animal or human by restraining a self-expanding stent in
a sheath and retracting the sheath such that the outside diameter of the
body increases and engages the inner surface of the tubular structure in
the animal or human.

[0024] The stent can be caused to engage an inner surface of the tubular
structure in the animal or human by mounting a balloon expandable stent
on a balloon and inflating the balloon such that the outside diameter of
the body increases and engages the inner surface of the tubular structure
in the animal or human.

[0025] These and other features, aspects, and advantages of the present
invention will become better understood upon consideration of the
following detailed description, drawings, and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a perspective view of one embodiment of a stent according
to the invention.

[0027] FIG. 2 is a side view of the stent of FIG. 1 in one unexpanded
state.

[0028]FIG. 3 is a side view of the stent of FIG. 1 in one expanded state.

[0029]FIG. 4 is a side view of an adjustment mechanism of the stent of
FIG. 1 shown partially in cross-section.

[0030] FIG. 5 is a detailed side view of a tension adjuster of the
adjustment mechanism and a complementary tensioning tool of the stent of
FIG. 1 shown partially in cross-section.

[0031] Like reference numerals will be used to refer to like parts from
Figure to Figure in the following description of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0032] Looking first at FIG. 1, there is shown an example embodiment of a
stent 10 according to the invention. The stent 10 includes an elastic
tubular body 12 having a first circumferential end 14 and an opposite
second circumferential end 16. The body is formed from a braiding of (i)
a first group of spaced apart helically wound first elastic strands 17a,
17b, 17c, 17d to 17m where m varies depending on the desired spacing
between the first elastic strands and the desired axial length of the
body 12 and (ii) a second group of spaced apart helically wound second
elastic strands 19a, 19b, 19c, 19d to 19n where n varies depending on the
desired spacing between the second elastic strands and the desired axial
length of the body 12. In the braiding, each strand can pass over one
strand and then under the adjacent strand wound in the same direction.

[0033] The first elastic strands 17a, 17b, 17c, 17d to 17m and the second
elastic strands 19a, 19b, 19c, 19d to 19n are helically wound with
respect to a longitudinal axis defined by the tubular body 12 to create a
braided configuration. The first elastic strands 17a, 17b, 17c, 17d to
17m and the second elastic strands 19a, 19b, 19c, 19d to 19n are
helically wound in opposite directions to create intersections (such as
21a, 21b, 21c, 21d, 21e) of the first elastic strands 17a, 17b, 17c, 17d
to 17m and the second elastic strands 19a, 19b, 19c, 19d to 19n. One or
more of the first elastic strands 17a, 17b, 17c, 17d to 17m can form the
first circumferential end 14 of the body 12, and one or more of the
second elastic strands 19a, 19b, 19c, 19d to 19n can form the second
circumferential end 16 of the body 12. The first elastic strands 17a,
17b, 17c, 17d to 17m and the second elastic strands 19a, 19b, 19c, 19d to
19n can be formed from a metallic material or a polymeric material.
Example metallic materials include cobalt and chromium alloys, stainless
steel, and nickel-titanium alloys.

[0034] Referring to FIGS. 1, 4 and 5, the stent 10 includes an adjustment
mechanism 24 for the moving the first end 14 of the body 12 toward or
away from the second end 16 of the body 12 of the stent 10. The
adjustment mechanism 24 includes a bracket 26, a tension adjustor 28 and
a tensioning wire 30 that is attached to the bracket 26 and the tension
adjustor 28. Guide rings 32 surround the tensioning wire 30 between the
bracket 26 and the tension adjustor 28. In one embodiment, the bracket
26, the tension adjustor 28, the tensioning wire 30, and the guide rings
32 are formed from the same material as the first elastic strands 17a,
17b, 17c, 17d to 17m and the second elastic strands 19a, 19b, 19c, 19d to
19n.

[0035] In the embodiment of FIGS. 1 to 5, the bracket 26 is attached to an
inner surface of the first circumferential end 14 of the body 12 using a
suitable attachment method such as welding, heat sealing or gluing. The
tension adjustor 28 is attached to an inner surface of the second
circumferential end 16 of the body 12 using a suitable attachment method
such as welding, heat sealing or gluing. The guide rings 32 are connected
to an inner surface of intersections 21f, 21g, 21h, 21i, 21j and 21k
using a suitable attachment method such as welding, heat sealing or
gluing.

[0036] Referring now to FIGS. 4 and 5, the construction of the bracket 26,
the tension adjustor 28 and the tensioning wire 30 can be explained in
more detail. The tension adjustor 28 includes a housing 34 having a hole
36 with internal threads 38 that mate with an external threaded section
42 of the tensioning wire 30. The housing 34 includes an opening 44 that
can be closed off with a hinged cover 46. The cover 46 prevents
accumulation of debris in the housing 34. The tensioning wire 30 includes
a spherical head 48 that is rotatably mounted in the bracket 26. A
proximal end of the tensioning wire 30 terminates in an enlarged head 50
that is located within an interior space 54 of the housing 34. The
enlarged head 50 of the tensioning wire 30 includes a hexagonal outer
surface 52 and a socket 55.

[0037] Still referring to FIGS. 4 and 5, the stent 10 can be supplied with
a tool 56 for varying the distance between the bracket 26 and the tension
adjustor 28. The tool 56 includes a cable 58 suitable for insertion into
the tubular structure in the animal or human. The cable 58 terminates in
a tip 62 for engaging the enlarged head 50 of the tensioning wire 30. In
the non-limiting example embodiment shown, the tip 62 of the tool 56 has
an outer wall 63 for engaging the hexagonal outer surface 52 of the
enlarged head 50 of the tensioning wire 30, and the tip 62 has a central
protrusion 64 for engaging the central socket 55 of the enlarged head 50
of the tensioning wire 30. The tip 62 of the tool 56 and/or the enlarged
head 50 of the tensioning wire 30 can be formed of materials that provide
magnetic attraction between the tip 62 and the head 50. The tool 56 can
be used with a sheath (not shown) that includes a passageway having a
distal opening wherein the passageway is dimensioned for insertion of the
cable 58 such that the tip 62 of the cable 58 can protrude beyond the
distal opening of the passageway. The sheath is dimensioned for insertion
into the tubular structure in the animal or human.

[0038] Having described the construction of the stent 10 and tool 56, the
use of the stent 10 and tool 56 can be explained. A catheter having a
first passageway and a second passageway can be introduced into the
tubular structure in the animal or human. The stent 10 can be grasped by
an endoscopic forceps, passed through the first passageway and then out
of a distal end of the first passageway in the catheter, and positioned
at a desired location in the tubular structure in the animal or human.
The tool 56 is then passed through the second passageway in the catheter
and then out of the distal end of the second passageway in the catheter.
After opening the cover 46, the tip 62 of the tool 56 is then positioned
to engage the hexagonal outer surface 52 of the enlarged head 50 of the
tensioning wire 30 as shown in FIG. 5. In an alternative configuration of
the tool, the tool is a multi-functional tool that also grasps the stent
10. This tool would only require a single passageway in the catheter.

[0039] When the stent 10 is first passed through the first passageway in
the catheter and positioned at a desired location in the tubular
structure in the animal or human, the stent 10 can have a configuration
as shown in FIG. 2 in which the stent 10 has an axial length X and an
outside diameter Y. With the tip 62 of the tool 56 engaging the hexagonal
outer surface 52 of the enlarged head 50 of the tensioning wire 30 as
shown in FIG. 5, the physician rotates the tool 56 in direction R in FIG.
5. Due to the engagement of the internal threads 38 of the housing 34 and
the external threaded section 42 of the tensioning wire 30, rotation in
direction R causes the tensioning wire 30 to move toward the opening 44
of the housing 34. As a result, the bracket 26 moves in direction -A and
the tension adjustor 28 moves in direction +A as shown in FIG. 3. The
guide rings 32 prevent any bowing of the tensioning wire 30 during
movement of the tensioning wire 30.

[0040] Because the bracket 26 is attached to an inner surface of the first
circumferential end 14 of the body 12 and the tension adjustor 28 is
attached to an inner surface of the second circumferential end 16 of the
body 12, the first circumferential end 14 and the second circumferential
end 16 of the body 12 move toward each other. Due to the helically wound
braided configuration of the first elastic strands 17a to 17m and the
second elastic strands 19a to 19n, movement of the first circumferential
end 14 and the second circumferential end 16 of the body 12 toward each
other causes the stent 10 to move in directions -B and +B into the
configuration as shown in FIG. 3 in which the stent 10 has an axial
length X' and an outside diameter Y' (which can be compared to the
configuration in which the stent 10 has an axial length X and an outside
diameter Y as shown in FIG. 2 and as shown in dashed lines in FIG. 3).
Note also how the outside diameter increases because the angle at the
intersection of the strands decreases from α1 in FIG. 2 to
α2 in FIG. 3. The increase in outside diameter from Y to Y'
causes the outside diameter Y' of the body 12 of the stent 10 to engage
the inner surface of the tubular structure in the animal or human. The
cover 46 can then be closed.

[0041] When repositioning or removal of the stent 10 is desired, the
catheter having the first passageway and the second passageway can be
introduced into the tubular structure in the animal or human. The tool 56
is then passed through the second passageway in the catheter and then out
of the distal end of the second passageway in the catheter. After opening
the cover 46, the tip 62 of the tool 56 is then positioned to engage the
hexagonal outer surface 52 of the enlarged head 50 of the tensioning wire
30 as shown in FIG. 5. With the tip 62 of the tool 56 engaging the
hexagonal outer surface 52 of the enlarged head 50 of the tensioning wire
30 as shown in FIG. 5, the physician rotates the tool 56 in a direction
opposite to direction R in FIG. 5. This causes the stent 10 to move back
into the configuration as shown in FIG. 2 in which the stent 10 has an
axial length X and an outside diameter Y. An endoscopic forceps is passed
through the first passageway and then out of a distal end of the first
passageway in the catheter, and the stent can be grasped for
repositioning at another desired location, or removal from the tubular
structure in the animal or human. After repositioning at another desired
location, the outside diameter of the stent 10 can be enlarged for
engagement with the inner surface of the tubular structure in the animal
or human as described above.

[0042] When the stent 10 is a self-expanding stent, another method can be
used. The stent 10 can be restrained within a sheath, passed through a
passageway in a catheter, and positioned at a desired location in the
tubular structure in the animal or human. The sheath can be retracted to
expose the stent 10 and allow the stent 10 to self-expand to have the
configuration as shown in FIG. 3 in which the stent 10 has an axial
length X' and an outside diameter Y'. This causes the outside diameter of
the body 12 of the stent 10 to engage an inner surface of the tubular
structure in the animal or human. Thereafter, the stent 10 can be
repositioned or removed as desired. Specifically, stent 10 can be caused
to move back into the configuration as shown in FIG. 2 in which the stent
10 has an axial length X and an outside diameter Y and repositioned or
removed as explained above.

[0043] When the stent 10 is a balloon expandable stent, another method can
be used. A delivery catheter assembly with an expandable balloon is used.
The stent 10 is mounted on the balloon and the catheter assembly is
pushed into the implantation site. Then, the balloon is inflated,
radially applying a force inside the stent 10, and the stent 10 is
expanded to have the configuration as shown in FIG. 3 in which the stent
10 has an axial length X' and an outside diameter Y'. This causes the
outside diameter of the body 12 of the stent 10 to engage an inner
surface of the tubular structure in the animal or human. Thereafter, the
stent 10 can be repositioned or removed as desired. Specifically, stent
10 can be caused to move back into the configuration as shown in FIG. 2
in which the stent 10 has an axial length X and an outside diameter Y and
repositioned or removed as explained above.

[0044] Other arrangements of the bracket 26, the tension adjustor 28, the
tensioning wire 30, and the guide rings 32 of the stent 10 are suitable.
For example, the bracket 26 and the tension adjustor 28 can be attached
at any of the intersections 21. The guide rings 32 can be omitted in
certain embodiments. Also, more than one adjustment mechanism 24
including the bracket 26, the tension adjustor 28, and the tensioning
wire 30 can be used. When using different numbers of adjustment
mechanisms, one has the ability to manually adjust the outside diameter
of either the whole stent or any part(s) of the stent.

[0045] Thus, the invention provides a manually adjustable variable outside
diameter stent. The stent can be repositioned in, or removed from, a
tubular structure in the body of an animal or human after being deployed.

[0046] Although the present invention has been described in detail with
reference to certain embodiments, one skilled in the art will appreciate
that the present invention can be practiced by other than the described
embodiments, which have been presented for purposes of illustration and
not of limitation. Therefore, the scope of the appended claims should not
be limited to the description of the embodiments contained herein.